Compact Planar 3.5/5.5 GHz Dual Band MIMO USB Dongle Antenna for WiMAX Applications

This paper presents a compact planar 3.5 GHz /5.5 GHz dual-band multiple input multiple output (MIMO) USB dongle antenna for WiMAX applications. Each antenna element has rectangular patch radiator fed by microstrip line bend. For miniaturization of antenna elements a U-shaped slot is cut in the ground plane of each antenna element with one end open and other end short. The proposed MIMO antenna has two similar elements and for improving coupling a tapered inverted T-shaped slot is cut in between the antenna elements at the ground plane side. The MIMO antenna has achieved coupling less than -20.2 dB in lower band (3.45-3.59 GHz) and less than -21.5 dB in upper band (5.46-5.58 GHz). The measured and simulated results show good agreement in both the bands. Moreover, the proposed design is also tested for its gain, efficiency, and envelope correlation coefficient at 3.5 GHz and 5.5 GHz, which shows that the proposed dual-band MIMO USB dongle antenna is suitable for WiMAX applications.